Many ultrasonic imaging systems operate by transmitting ultrasonic energy from a transmitter toward a target object, and detecting that portion of the transmitted ultrasonic energy that has been reflected by the target object. Detecting the reflected ultrasonic energy may be accomplished by an array of ultrasonic receivers. Such systems exist, for example, to produce images of fingerprints corresponding to a finger that is placed on a platen.
Ideally, the ultrasonic energy that is transmitted travels straight to the target object, and any ultrasonic energy reflected by the object travels straight to a receiver. In practice, some energy does not travel so directly to and from the target object. Some of the ultrasonic energy is diffracted and some is reflected by objects other than the target object. As such, the ultrasonic energy emanating from the transmitter does not remain well-organized as the energy travels from the transmitter to the target object and then to the receivers. As the organization of the ultrasonic energy degrades, so too does the ability to generate a clear image of the target object because some of the energy detected by a particular receiver in the receiver array did not travel straight from the transmitter to the target object and then straight to that receiver. Therefore, it would be useful to have a way of mitigating the loss of clarity arising from the fact that some ultrasonic energy received at an array of receivers has not traveled straight from the transmitter to the target object, and then straight from the target object to a particular receiver in the array.